BX8811 Installation Instructions
Tail Light Wiring Kit
The Tail Light Wiring Kit connects the tail, brake, and turn
signal lights of the motorhome (or other tow vehicle) to the
tail, brake, and turn signal lights of the towed vehicle.
Type A: Vehicles with standard red turn signals.
NOTE: Some motorhomes have separate amber turn
signals and red brake lights which requires the use of a tail
light converter to change from a 4 wire system to a three
wire system. A tail light converter is not supplied with the
Tail Light Wiring Kit, but is available through your local
supply center.
Type C: Vehicles with separate amber or red signals (One
brake light wire comes out of the other brake light
socket).
WARNING: Incorrect wiring may result in blown fuses,
damaged wiring or computer systems, fire, or bodily injury.
Automatic Equipment recommends installation of this kit by
a trained professional. Automatic Equipment will not be
responsible for any personal property damage, or bodily
injury caused by incorrect wiring or misuse of this product.
NOTE: In Type A wiring systems only, access may be
made under the dash where existing wires extend from
the turn signal switch, down and rearward to the tail
lights.
NOTE: In the wiring systems type B and C, the amber
signals will only operate from the towed vehicles system.
The red brake lights will function as turn signals when
operated from the towing vehicle.
3. DO NOT PRE-STRIP WIRES. Start the wire piercing
screws into the tail light connector.
Tools Required
Wire terminal crimper
Wire stripper
Small wire cutter
Standard screw driver
trical Tape
12 Volt D.C. continuity tester with needle point.
Type B: Vehicles with separate amber or red signals (Brake
light wire splits before the lights).
Elec-
Check the parts in the kit against the parts list to
familiarize yourself with each item.
Parts List
Ref.
Part
No. Qty. No.
Description
1
1 294-0562 ....................... Wire Harness, 26 Ft., 4-wire
2
1 294-0560 .............................. 9 Terminal Diode Block
3
1 294-0563 ........................ Wire Splitter, 14 Ga, Tinned
4
1 294-0250 .......... Butt Connector, 16-14 Ga. Insulated
5
5 290-0297 ....................... Nylon Cable Tie, Beaded, 5"
6
9 201-0462 ... #6-32 x 1/2 Screw, Wire piercing washer
Installation
1. Starting in the engine compartment of the towed vehicle,
run the 26 ft. harness through the firewall, under the
drivers side door sill plate, under the back seat, and into
the trunk area. Depending on the motorhome set up, the
wire at the front of the engine compartment should be
wired into either a 4-wire or 6-wire trailer plug that is
mounted to the front of the towed vehicle.
2. Three wiring diagrams are shown. Identify your type of
vehicle wiring, then follow the wiring diagram which
pertains to your vehicle.
4. Make sure that the white wire is grounded to the vehicle
chassis. It is also important to have a good ground on
the towing vehicle.
Use a 12 Volt D.C. continuity lamp tester with a needle
point prod to identify the “hot” wires which power the
brake and tail lights. Ground one end of tester, and
insert prod through the insulation of each wire to identify.
At this point the 4-conductor cable should be cut to
length, leaving enough slack to reach the tail light
connector. NOTE: Vehicle lights must be on and the
corresponding turn signals will have to be operating in
order for wires to be “hot”.
NOTE: When tapping into the wires under the dash,
make sure to select the wires extending to the rear
lights, not those extending to the front lights.
5. After the tail light and turn signal wires are identified and
marked, shut off the power then cut each wire. Place
the wires from the front under their respective screws and
tighten down. DO NOT OVER TIGHTEN. Place the
wires to the back lights of the towed vehicle under their
respective screws and tighten down. Do the same with
the wires from the 26 ft. 4- conductor cable. (See wiring
diagram for your type of car). If the wire is a light gage,
the wire piercing screws may not penetrate the wire
casing properly. In this instance, doubling the wire under
the screw should allow it to make a good connection.
Automatic Equipment Mfg. Co.
One Mill Road, Industrial Park l Pender, Nebraska 68047
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This completes wiring of the towed vehicle. Check to
make sure the vehicle’s tail, brake, and turn signal lights
operate the same as they did prior to installation of the
tail light connector and the 4-conductor cable. Electrical
tape can be used to keep the diode block from shorting
against part of the car.
Connecting Two Vehicles Together
1. If the towing vehicle is already wired for towing check to
see what type of existing socket it has, a mating plug
will need to be purchased. Use the 12 volt lamp tester to
identify each pin in the socket, and connect the 4-wire
cable according to the wiring diagram color scheme.
2. If the towing vehicle is not wired for towing, a pigtail will
need to be purchased and wired into the existing wiring
of the towing vehicle as is described below. NOTE: Be
sure there is sufficient length to reach the plug on the
towed vehicle. NOTE: Self stripping wire tap connectors
will also have to be purchased to “tap into” the existing
wiring of the towing vehicle.
3. Connect the white wire from the new pigtail to a suitable
ground. To connect the other three wires extending from
the new pigtail to the existing towing vehicle wiring, it is
necessary to identify the appropriate wires at the rear of
the Towing vehicle. Use a 12 volt D.C. continuity lamp to
identify the appropriate “hot” wires. The vehicles lights,
and turn signals will have to be activated in order for
there to be current traveling through the wires.
NOTE: If the towing vehicle is equipped with separate
amber turn signals and red brake lights, use the same
procedure to identify the brake light wire. A tail light
converter (not included) is needed to convert the amber/
red 4-wire system to the standard “red only” 3-wire
system.
NOTE: A heavy duty flasher unit may be required in
the towing vehicle to power the added circuit load of a
towed vehicle.
This completes installation of the Tail Light Wiring Kit.
To test system, simply plug towed vehicles pigtail into
the towing vehicles socket, and turn on the towing
vehicles lights. Test each turn signal and the brake
lights. If lights do not work properly, there must be a
loose connection, or a wiring error. Recheck to assure
all connections were made correctly, especially the
ground connections. If your third brake light blinks with a
turn signal continue reading.
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Wiring Third Brake Light (Optional)
On some vehicles with separate amber turn signals,
the third brake light or the light in the back window may
blink with one of the turn signals while in the towing
mode only. To prevent the third brake light from blinking,
complete the following steps. NOTE: After completing
these steps the third brake light will not function at all
when in the towing mode and will function normally when
driving the vehicle.
1. While applying power to the brake lights, Use a 12 Volt
D.C. continuity tester to locate the "hot" wire feeding
power to the positive side of the third brake light.
2. Relieve power to the brake lights and cut the "hot" wire
located in step 1. NOTE: Be sure to leave enough wire
extending from the positive side of the third brake light to
allow for splicing. (About 6-12 inches) Use electrical tape
to cover the other exposed end of the cut wire.
4. Obtain a piece of 16 gage stranded wire (available at
most automotive stores) long enough to reach from the
9-screw diode block to the "hot" wire extending from the
positive side of the third brake light.
5. Using a butt connector (available at most automotive
stores) splice one end of the length of wire acquired to
the wire extending from the positive side of the third
brake light.
6. Place the other end of the wire under either the "L" or "R"
wire piercing screw on the "from front of towed car" side
of the diode block. NOTE: There is already a wire under
both of these screws so this new wire must be placed on
the opposite side of the screw as the existing wire. Do
not stack the wires on top of each other under the wire
piercing screw.
7. Be sure to test the entire system before towing.
DEALER OR INSTALLER: BE CERTAIN THE
USER RECEIVES ALL INSTRUCTION SHEETS.
DIAGRAM FOR TYPE A VEHICLES
(Vehicles with standard red turn signals)
DIAGRAM FOR TYPE B VEHICLES
(Vehicles with separate amber turn signals)
(Brake light wire splits before the lights)
DIAGRAM FOR TYPE C VEHICLES
(Vehicles with separate amber turn signals)
(Power for one brake light comes from other
lights socket)
Cut the main brake wire coming from the front, and
strip it back approximately 1/4". Use the butt connector
provided to connect the stripped wire and the single wire
on the splitter, crimp with a wire terminal crimper. Attach
the two ends of the splitter to the left and right screws on
the front of the connector.
Attach the brake wire going to the back brake lights to
the appropriate terminal, depending on whether the wire
goes to the left or the right brake light first.
Cut the wire connecting the first brake light to the
second brake light. Connect the wire that goes to the
second brake light to the appropriate terminal, which will
correspond with the side the second light is on.
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DIAGRAMS FOR TYPE C VEHICLES
Trouble Shooting
PROBLEM - LIGHTS WORK CORRECTLY BUT DIM.
POSSIBLE CAUSES/SOLUTIONS
A Bad, loose or faulty ground on either or both vehicles.
B Short circuit in the system on either or both vehicles.
C Motorhome (towing vehicle) alternator too small.
D Motorhome (towing vehicle) wiring is too light to handle extra power requirements.
E Motorhome (towing vehicle) may require a heavy duty flasher unit to handle the extra load.
F Adding and additional ground between both vehicles may help.
PROBLEM - OTHER LIGHTS DIM WHEN TURN SIGNALS ARE TURNED ON.
POSSIBLE CAUSES/SOLUTIONS
A Feedback is present caused by a bad ground or short.
B Motorhome (towing vehicle) has a weak battery. Replace or start motorhome and try again.
C There could be a bulb on the towed vehicle that is bad or shorted out.
PROBLEM - THIRD BRAKE LIGHT BLINKS WITH THE TURN SIGNALS.
POSSIBLE CAUSES/SOLUTIONS
A Follow the optional wiring instructions of the third brake light.
PROBLEM - BOTH TURN SIGNALS FLASH TOGETHER.
POSSIBLE CAUSES/SOLUTIONS
A The diode block is wired into the system before the existing brake wires split. Move the block to a point after the
existing brake wires are separate.
B Type "C" vehicles must have the jumper wire removed from between the left and right brake lights.
PROBLEM - ONLY ONE TURN SIGNAL WORKS.
POSSIBLE CAUSES/SOLUTIONS
A Bad diode block.
B The diode block is wired in after the existing wires split, therefore both wires from the back of the car must be connected
separately to the diode block.
PROBLEM - DIODE BLOCK IS WARM TO THE TOUCH.
POSSIBLE CAUSES/SOLUTIONS
A Under normal use the diode block will become warm to the touch. This is not a cause for alarm.
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© 1994 Automatic Equipment
Mfg. Co., Inc.
Pender, NE 68047